Kiki Bertens is wrapped up warm for the occasion. She's wearing a jacket and leggings - presumably to keep her injured calf in hold.

The Dutch player looks like she's moving freely at the moment - far more than Serena Williams is anyway, who looks like she's not 100%

A Bertens drop shot sees her hold her serve to lead 2-0. 

Image source, AP

Russell Fuller
BBC tennis correspondent on BBC Radio 5 live sports extra

"It's an absolute disgrace to see a women's semi-final at a Grand Slam tournament take place in front of so few people."

Mary Pierce
Former French Open champion on BBC Radio 5 live sports extra

"That will give Kiki some confidence that Serena may not be feeling great. She'll be thinking 'if  I hang in there and fight, anything could happen."

Serena Williams is having a right stinker early doors. 

Bertens has three break points as her opponent fails to place her shots within the tramlines.

The American rescues one with an ace, then another after Bertens hits long.

But Williams serves a double fault and Bertens breaks. Curious. 

Serena Williams, world number one and defending champion, will get us underway on Philippe-Chatrier Court.

Mary Pierce
Former French Open champion on BBC Radio 5 live sports extra

"It's quite incredible - Kiki's been on the tour for a while. All of a sudden she's having incredible results. She's obviously very relaxed and has nothing to lose in this match today. You expect Serena to win - but special things can happen in Grand Slams."

You can listen to live coverage of Serena Williams v Kiki Bertens, followed by Andy Murray v Stan Wawrinka, on BBC Radio 5 live sports extra.

Just click the play button at the top of this page. Et voila. 

Mary Pierce
Former French Open champion on BBC Radio 5 live sports extra

"I was looking at the weather and thought this is not the type of conditions you want to play tennis in. You can actually sometimes play a whole match on the clay in drizzly conditions. The balls get very heavy so it’s really not easy. The ball will be slower so it will be more difficult for Serena to hit winners."

Image source, BBC Sport

There will be plenty of dark fluffy things in the sky over Paris - the key is how many drops of the wet stuff come out of them.

Kiki Bertens has made it through to her first Grand Slam semi-final but she's being hampered by injury. 

The Dutch 24-year-old needed treatment in her quarter-final match on Thursday and has had further tests this morning, but she has been deemed fit to play.

Not ideal before meeting the world number one. 

Image source, Getty Images

Serena Williams was given a severe test by Kazakhstan's Yulia Putintseva in the quarter-finals on Thursday, but eventually prevailed 5-7 6-4 6-1.

Williams is vying for her fourth French Open title, and her 22nd Grand Slam.

Fellow world number one Novak Djokovic won in straight sets 6-3 7-5 6-3 against Tomas Berdych of Czech Republic.

But the Serb, who is only missing the French Open title from his collection, courted a bit of controversy after he threw his racquet down in anger and narrowly missed a line judge. 

World number 58 Kiki Bertens pulled off another shock by beating Swiss eighth seed Timea Bacsinszky 7-5 6-2, while Dominic Thiem beat Belgian 12th seed David Goffin 4-6 7-6 (9-7) 6-4 6-1 to reach his first Grand Slam semi-final.

Image source, Getty Images

Welcome along!

Here's what's in store this afternoon:

Philippe-Chatrier Court 

• Serena Williams v Kiki Bertens (12:00 BST)
• Andy Murray v Stan Wawrinka (not before 14:00 BST)

Suzanne-Lenglen Court

• Garbine Muguruza v Sam Stosur (12:00 BST)
• Novak Djokovic v Dominic Theim (not before 14:00 BST)

When you realise it's Friday and there's a French Open semi-final live text coming...

Image source, Getty Images